This invention relates to an automatic paste board box forming machine by which a developed paste board is bent in order and a paste board box is assembled, espacially to an automatic paste board box forming mechine in which various type of operator used for paste board assembling is operated by cam through wire slidably inserted in a hollow and shelled cable, by which a driving force transmitting mechanism of each operator is simplified.
In the prior art, the paste board box forming mechine which forms paste board box storing cloths, food, etc. comprised assembling of link mechanism, gear mechanism, etc., where a driving force of an electric motor is transmitted to each operator. If the paste board box having various sizes is assembled with a single box forming machine, operators bending each side of box must be exchanged and a power transmitting mechanism should be greatly changed. In the case of the box forming machine having such exchanged mechanism, a construction of the box forming machine becomes complex to resulting in many troubles in addition to the high cost of the machine.
In the case of a power transmitting mechanism having a combination of a link mechanism and a gear mechanism, if two or more paste board are fed to a paper bending mechanism, an abnormal excess load is imposed on the power transmitting mechanism by bending a paste board with operators, and a link mechanism which is a weak point in the construction in a power transmitting mechanism is destroyed. For a purpose of preventing this destruction, in the prior art, a sear pin is provided, which is sheared when a transmitting stress over constant value caused at the rotational parts of the power transmitting mechanism, so that destruction of a transmitting mechanism is prevented. However, the sear pin does not always suitably operate. For example, if a weak sear pin is used, even in a light load, the sear pin is often sheared during a normal paper box bending process. If a strong sear pin is used, the power transmitting mechanism is in danger of destruction before the shear pin is sheared.
Also, in prior paste board box forming machine, there are a types of the paste board box forming machine in which air pressure machine such as air cylinder is used to make the operator to work. In the type of the paste board box forming machine, a complex process, which is not able to conduct with a transmitting mechanism comprising the gear mechanism, can be carried out with a simple link mechanism connecting an air cylinder and an operator and with an air supplying hose connecting a cylinder and a compressor in addition to with an air cylinder.
However, in case of use of an air pressure mechanism, at first, the energy loss is large and the capacity of electric motor driving an air pressure mechanism must be large because mechanical energy is changed to compressed air pressure and still more to mechanical energy. In the second place, a jet sound is generated between a compressor and an air pressure storing tank and between latter tank and an air cylinder when compressed air is supplied into or exhausted from these mechanisms. This phenomenon causes noise pollution. Also, a going-and-returning-response operation of air cylinder is restricted in the capacity and the construction of magnet valve by which compressed air is switched to air cylinder, so that the paste board box cannot be formed with high speed.